The long-term goal of the proposed research is to develop and test a set of experimental and analytical techniques for exploring: (1) water flux and its effect on formed elements and macromolecules in pulsatile blood flow at arterial walls, (2) the way this water flux and the distribution of resistances to water flux plus the compliance of the arterial wall to the mobile water can contribute to the distribution of forces that will lead to the desquamation of endothelial cells in the presence of a pulse, and (3) the way vasoactive substances in the blood (as mediated by concentration polarization when it occurs) and physical factors such as arterial wall properties, mean pressure, and pulse height can influence the forces that lead to desquamation. Work thus far has established the magnitude of the water flux with and without endothelium and has resulted in a method of determining pore characteristics. In the coming year the size and number density of the pores will be established and models for concentration polarization will be developed.